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[POWERPC] 85xx: Add support for relocatable kernel (and booting at non-zero)

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Added support to allow an 85xx kernel to be run from a non-zero physical
address (useful for cooperative asymmetric multiprocessing situations and
kdump).  The support can be configured at compile time by setting
CONFIG_PAGE_OFFSET, CONFIG_KERNEL_START, and CONFIG_PHYSICAL_START as
desired.

Alternatively, the kernel build can set CONFIG_RELOCATABLE.  Setting this
config option causes the kernel to determine at runtime the physical
addresses of CONFIG_PAGE_OFFSET and CONFIG_KERNEL_START.  If
CONFIG_RELOCATABLE is set, then CONFIG_PHYSICAL_START has no meaning.
However, CONFIG_PHYSICAL_START will always be used to set the LOAD program
header physical address field in the resulting ELF image.

Currently we are limited to running at a physical address that is a
multiple of 256M.  This is due to how we map TLBs to cover
lowmem.  This should be fixed to allow 64M or maybe even 16M alignment
in the future.  It is considered an error to try and run a kernel at a
non-aligned physical address.

All the magic for this support is accomplished by proper initialization
of the kernel memory subsystem and use of ARCH_PFN_OFFSET.

The use of ARCH_PFN_OFFSET only affects normal memory and not IO mappings.
ioremap uses map_page and isn't affected by ARCH_PFN_OFFSET.

/dev/mem continues to allow access to any physical address in the system
regardless of how CONFIG_PHYSICAL_START is set.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Kumar Gala 2008-04-22 04:22:34 +10:00 committed by Paul Mackerras
parent 96f1bb8a41
commit 37dd2badcf
11 changed files with 136 additions and 23 deletions
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71
arch/powerpc/Kconfig
View file

@ -656,21 +656,76 @@ config LOWMEM_SIZE
hex "Maximum low memory size (in bytes)" if LOWMEM_SIZE_BOOL
default "0x30000000"
config RELOCATABLE
bool "Build a relocatable kernel (EXPERIMENTAL)"
depends on EXPERIMENTAL && ADVANCED_OPTIONS && FLATMEM && FSL_BOOKE
help
This builds a kernel image that is capable of running at the
location the kernel is loaded at (some alignment restrictions may
exist).
One use is for the kexec on panic case where the recovery kernel
must live at a different physical address than the primary
kernel.
Note: If CONFIG_RELOCATABLE=y, then the kernel runs from the address
it has been loaded at and the compile time physical addresses
CONFIG_PHYSICAL_START is ignored. However CONFIG_PHYSICAL_START
setting can still be useful to bootwrappers that need to know the
load location of the kernel (eg. u-boot/mkimage).
config PAGE_OFFSET_BOOL
bool "Set custom page offset address"
depends on ADVANCED_OPTIONS
help
This option allows you to set the kernel virtual address at which
the kernel will map low memory. This can be useful in optimizing
the virtual memory layout of the system.
Say N here unless you know what you are doing.
config PAGE_OFFSET
hex "Virtual address of memory base" if PAGE_OFFSET_BOOL
default "0xc0000000"
config KERNEL_START_BOOL
bool "Set custom kernel base address"
depends on ADVANCED_OPTIONS
help
This option allows you to set the kernel virtual address at which
the kernel will map low memory (the kernel image will be linked at
this address). This can be useful in optimizing the virtual memory
layout of the system.
the kernel will be loaded. Normally this should match PAGE_OFFSET
however there are times (like kdump) that one might not want them
to be the same.
Say N here unless you know what you are doing.
config KERNEL_START
hex "Virtual address of kernel base" if KERNEL_START_BOOL
default PAGE_OFFSET if PAGE_OFFSET_BOOL
default "0xc2000000" if CRASH_DUMP
default "0xc0000000"
config PHYSICAL_START_BOOL
bool "Set physical address where the kernel is loaded"
depends on ADVANCED_OPTIONS && FLATMEM && FSL_BOOKE
help
This gives the physical address where the kernel is loaded.
Say N here unless you know what you are doing.
config PHYSICAL_START
hex "Physical address where the kernel is loaded" if PHYSICAL_START_BOOL
default "0x02000000" if PPC_STD_MMU && CRASH_DUMP
default "0x00000000"
config PHYSICAL_ALIGN
hex
default "0x10000000" if FSL_BOOKE
help
This value puts the alignment restrictions on physical address
where kernel is loaded and run from. Kernel is compiled for an
address which meets above alignment restriction.
config TASK_SIZE_BOOL
bool "Set custom user task size"
depends on ADVANCED_OPTIONS
@ -717,9 +772,17 @@ config PIN_TLB
endmenu
if PPC64
config KERNEL_START
config PAGE_OFFSET
hex
default "0xc000000000000000"
config KERNEL_START
hex
default "0xc000000002000000" if CRASH_DUMP
default "0xc000000000000000"
config PHYSICAL_START
hex
default "0x02000000" if CRASH_DUMP
default "0x00000000"
endif
source "net/Kconfig"

11
arch/powerpc/kernel/head_fsl_booke.S
View file

@ -371,6 +371,17 @@ skpinv: addi r6,r6,1 /* Increment */
bl early_init
#ifdef CONFIG_RELOCATABLE
lis r3,kernstart_addr@ha
la r3,kernstart_addr@l(r3)
#ifdef CONFIG_PHYS_64BIT
stw r23,0(r3)
stw r25,4(r3)
#else
stw r25,0(r3)
#endif
#endif
mfspr r3,SPRN_TLB1CFG
andi. r3,r3,0xfff
lis r4,num_tlbcam_entries@ha

4
arch/powerpc/kernel/prom.c
View file

@ -53,6 +53,7 @@
#include <asm/pci-bridge.h>
#include <asm/phyp_dump.h>
#include <asm/kexec.h>
#include <mm/mmu_decl.h>
#ifdef DEBUG
#define DBG(fmt...) printk(KERN_ERR fmt)
@ -978,7 +979,10 @@ static int __init early_init_dt_scan_memory(unsigned long node,
}
#endif
lmb_add(base, size);
memstart_addr = min((u64)memstart_addr, base);
}
return 0;
}

2
arch/powerpc/kernel/setup_64.c
View file

@ -435,7 +435,7 @@ void __init setup_system(void)
printk("htab_address = 0x%p\n", htab_address);
printk("htab_hash_mask = 0x%lx\n", htab_hash_mask);
#if PHYSICAL_START > 0
printk("physical_start = 0x%x\n", PHYSICAL_START);
printk("physical_start = 0x%lx\n", PHYSICAL_START);
#endif
printk("-----------------------------------------------------\n");

2
arch/powerpc/mm/fsl_booke_mmu.c
View file

@ -202,7 +202,7 @@ adjust_total_lowmem(void)
cam_max_size = max_lowmem_size;
/* adjust lowmem size to max_lowmem_size */
ram = min(max_lowmem_size, total_lowmem);
ram = min(max_lowmem_size, (phys_addr_t)total_lowmem);
/* Calculate CAM values */
__cam0 = 1UL << 2 * (__ilog2(ram) / 2);

5
arch/powerpc/mm/init_32.c
View file

@ -59,7 +59,10 @@ DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long total_memory;
unsigned long total_lowmem;
phys_addr_t memstart_addr;
phys_addr_t memstart_addr = (phys_addr_t)~0ull;
EXPORT_SYMBOL(memstart_addr);
phys_addr_t kernstart_addr;
EXPORT_SYMBOL(kernstart_addr);
phys_addr_t lowmem_end_addr;
int boot_mapsize;

3
arch/powerpc/mm/init_64.c
View file

@ -72,7 +72,8 @@
#warning TASK_SIZE is smaller than it needs to be.
#endif
phys_addr_t memstart_addr;
phys_addr_t memstart_addr = ~0;
phys_addr_t kernstart_addr;
void free_initmem(void)
{

5
arch/powerpc/mm/mem.c
View file

@ -216,7 +216,7 @@ void __init do_init_bootmem(void)
unsigned long total_pages;
int boot_mapsize;
max_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
max_low_pfn = max_pfn = lmb_end_of_DRAM() >> PAGE_SHIFT;
total_pages = (lmb_end_of_DRAM() - memstart_addr) >> PAGE_SHIFT;
#ifdef CONFIG_HIGHMEM
total_pages = total_lowmem >> PAGE_SHIFT;
@ -232,7 +232,8 @@ void __init do_init_bootmem(void)
start = lmb_alloc(bootmap_pages << PAGE_SHIFT, PAGE_SIZE);
boot_mapsize = init_bootmem(start >> PAGE_SHIFT, total_pages);
min_low_pfn = MEMORY_START >> PAGE_SHIFT;
boot_mapsize = init_bootmem_node(NODE_DATA(0), start >> PAGE_SHIFT, min_low_pfn, max_low_pfn);
/* Add active regions with valid PFNs */
for (i = 0; i < lmb.memory.cnt; i++) {

5
include/asm-powerpc/kdump.h
View file

@ -11,16 +11,11 @@
#ifdef CONFIG_CRASH_DUMP
#define PHYSICAL_START KDUMP_KERNELBASE
#define KDUMP_TRAMPOLINE_START 0x0100
#define KDUMP_TRAMPOLINE_END 0x3000
#define KDUMP_MIN_TCE_ENTRIES 2048
#else /* !CONFIG_CRASH_DUMP */
#define PHYSICAL_START 0x0
#endif /* CONFIG_CRASH_DUMP */
#ifndef __ASSEMBLY__

45
include/asm-powerpc/page.h
View file

@ -12,6 +12,7 @@
#include <asm/asm-compat.h>
#include <asm/kdump.h>
#include <asm/types.h>
/*
* On PPC32 page size is 4K. For PPC64 we support either 4K or 64K software
@ -42,8 +43,23 @@
*
* The kdump dump kernel is one example where KERNELBASE != PAGE_OFFSET.
*
* To get a physical address from a virtual one you subtract PAGE_OFFSET,
* _not_ KERNELBASE.
* PAGE_OFFSET is the virtual address of the start of lowmem.
*
* PHYSICAL_START is the physical address of the start of the kernel.
*
* MEMORY_START is the physical address of the start of lowmem.
*
* KERNELBASE, PAGE_OFFSET, and PHYSICAL_START are all configurable on
* ppc32 and based on how they are set we determine MEMORY_START.
*
* For the linear mapping the following equation should be true:
* KERNELBASE - PAGE_OFFSET = PHYSICAL_START - MEMORY_START
*
* Also, KERNELBASE >= PAGE_OFFSET and PHYSICAL_START >= MEMORY_START
*
* There are two was to determine a physical address from a virtual one:
* va = pa + PAGE_OFFSET - MEMORY_START
* va = pa + KERNELBASE - PHYSICAL_START
*
* If you want to know something's offset from the start of the kernel you
* should subtract KERNELBASE.
@ -51,20 +67,33 @@
* If you want to test if something's a kernel address, use is_kernel_addr().
*/
#define PAGE_OFFSET ASM_CONST(CONFIG_KERNEL_START)
#define KERNELBASE (PAGE_OFFSET + PHYSICAL_START)
#define LOAD_OFFSET PAGE_OFFSET
#define KERNELBASE ASM_CONST(CONFIG_KERNEL_START)
#define PAGE_OFFSET ASM_CONST(CONFIG_PAGE_OFFSET)
#define LOAD_OFFSET ASM_CONST((CONFIG_KERNEL_START-CONFIG_PHYSICAL_START))
#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_FLATMEM)
#ifndef __ASSEMBLY__
extern phys_addr_t memstart_addr;
extern phys_addr_t kernstart_addr;
#endif
#define PHYSICAL_START kernstart_addr
#define MEMORY_START memstart_addr
#else
#define PHYSICAL_START ASM_CONST(CONFIG_PHYSICAL_START)
#define MEMORY_START (PHYSICAL_START + PAGE_OFFSET - KERNELBASE)
#endif
#ifdef CONFIG_FLATMEM
#define pfn_valid(pfn) ((pfn) < max_mapnr)
#define ARCH_PFN_OFFSET (MEMORY_START >> PAGE_SHIFT)
#define pfn_valid(pfn) ((pfn) >= ARCH_PFN_OFFSET && (pfn) < (ARCH_PFN_OFFSET + max_mapnr))
#endif
#define virt_to_page(kaddr) pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)
#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT)
#define virt_addr_valid(kaddr) pfn_valid(__pa(kaddr) >> PAGE_SHIFT)
#define __va(x) ((void *)((unsigned long)(x) + PAGE_OFFSET))
#define __pa(x) ((unsigned long)(x) - PAGE_OFFSET)
#define __va(x) ((void *)((unsigned long)(x) - PHYSICAL_START + KERNELBASE))
#define __pa(x) ((unsigned long)(x) + PHYSICAL_START - KERNELBASE)
/*
* Unfortunately the PLT is in the BSS in the PPC32 ELF ABI,

6
include/asm-powerpc/page_32.h
View file

@ -1,6 +1,12 @@
#ifndef _ASM_POWERPC_PAGE_32_H
#define _ASM_POWERPC_PAGE_32_H
#if defined(CONFIG_PHYSICAL_ALIGN) && (CONFIG_PHYSICAL_START != 0)
#if (CONFIG_PHYSICAL_START % CONFIG_PHYSICAL_ALIGN) != 0
#error "CONFIG_PHYSICAL_START must be a multiple of CONFIG_PHYSICAL_ALIGN"
#endif
#endif
#define VM_DATA_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS32
#ifdef CONFIG_NOT_COHERENT_CACHE